The Hummer H2 is an enjoyable vehicle for towing the boat, blasting through the desert, or taking to the trails. A high-performance Vortec engine demands a reliable and efficient cooling system to keep your Hummer on the road and out of the shop. The Mishimoto racing thermostat is an easy upgrade for both performance and dependability. The Mishimoto Hummer H2 Racing Thermostat is precision engineered to provide your vehicle with optimal cooling efficiency even in the most demanding environments. Mishimoto racing thermostats promote greater cooling efficiency by significantly decreasing high engine temperatures. Once the engine is fully warmed up, the Mishimoto racing thermostat will open at a lower temperature (160°F) compared to standard thermostats (186°F). This allows coolant to flow through the engine sooner, thus reducing and maintaining cooler engine temperatures. Mishimoto thermostats are digitally calibrated, utilize high-quality wax to ensure precise and consistent opening temperatures, and include a gasket for seamless, leak-free installation. As with all our products, this racing thermostat is guaranteed by the Mishimoto Lifetime Warranty